Systems and methods for diverting objects

ABSTRACT

In one embodiment, a conveyor system includes a conveyor belt having a plurality of conveyor belt rollers configured to divert objects on the conveyor belt, and a drive mechanism that engages the conveyor belt rollers, the drive mechanism being configured to drive the conveyor belt rollers, the drive mechanism being adjustable such that the conveyor belt rollers can be selectively driven in a first angular direction and a second, opposite angular direction so that objects can be selectively diverted to either side of the conveyor belt at a desired diverting angle.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority to copending U.S. provisionalapplication entitled, “Systems and Methods for a Variable AngleHigh-Speed Diverting Conveyor System,”having Ser. No. 60/762,227, filedJan. 26, 2006, which is entirely incorporated herein by reference.

BACKGROUND

It is often necessary to divert objects from a conveyor belt, forexample to another conveyor belt, for purposes of routing or positioningthe objects for processing of one type or another.

Recently, conveyor systems have been developed in which the conveyorbelt comprises a plurality of small, angled rollers that extend beyondthe top and bottom surfaces of the belt. With such systems, objectscarried by the conveyor belt, and more particularly by the rollerscontained within the belt, can be diverted from the belt by rotating therollers. The conveyor belt rollers can be caused to rotate using variousmethods. In one such method, the rollers are driven by selectivelybringing a friction plate located beneath the conveyor belt into and outof engagement with the rollers. When the plate engages the rollers, therollers are caused to rotate in response to the frictional forcesbetween the friction plate and the rollers. In another method,free-spinning rollers located below the conveyor belt are selectivelyengaged with and disengaged from the conveyor belt rollers, and frictionbetween the engaged rollers causes rotation of both sets of rollers inopposite directions.

Although the above-described conveyor systems provide significantadvantages in relation to diverting objects from a conveyor belt, somelimitations in their use still exist. For example, because the angles ofthe conveyor belt rollers are fixed, diverting can only be performed toone side of the conveyor belt and at a fixed diverting angle. Therefore,if it is desired to change the diverting direction or angle, theconveyor line must be shut down and the conveyor belt must be replacedwith a different conveyor belt having rollers arranged in a differentorientation.

A further disadvantage relates to roller slip. Specifically, when afriction plate is brought into contact with the rollers, the rollersmust accelerate from zero angular velocity to a final angular velocityproportional to the speed at which the conveyor belt is travelling.Given that the rollers cannot instantaneously accelerate to the finalangular velocity, roller slip occurs that causes wear to the rollers.The same phenomenon can occur, albeit to a lesser degree, in embodimentsthat employ free-spinning rollers to rotate the conveyor belt rollers.Specifically, although rotation of the free-spinning rollers reducesslip, slip can still occur during the period just after roller-to-rollercontact is made.

Furthermore, when the friction plate or the free-spinning rollers aredisengaged from the conveyor belt rollers, the conveyor belt rollers arefree to rotate, which can enable objects present on the conveyor belt todrift across the belt. Although such drift may be desirable in somesituations, it may be undesirable in situations in which it is desiredto precisely control the lateral position of an object on the conveyorbelt.

BRIEF DESCRIPTION OF THE DRAWINGS

The disclosed systems and methods can be understood with reference tothe following drawings. The components in the drawings are notnecessarily to scale.

FIG. 1 is a top perspective view of a first embodiment of a portion of aconveyor system.

FIG. 2A is a top perspective view of a drive roller module used in theconveyor system of FIG. 1.

FIG. 2B is a bottom perspective view of a drive roller module used inthe conveyor system of FIG. 1.

FIG. 3 is top perspective view of a further portion of the conveyorsystem of FIG. 1.

FIG. 4 is a bottom perspective view of a plurality of drive rollermodules used in the conveyor system of FIG. 1.

FIG. 5A is a view of the conveyor system portion shown in FIG. 3,illustrating diverting action in a first direction.

FIG. 5B is a view of the conveyor system portion shown in FIG. 3,illustrating diverting action in a second direction.

FIG. 6A is a top view of a drive roller module, illustrating pivoting ofthe module in a first angular direction.

FIG. 6B is a top view of a drive roller module, illustrating pivoting ofthe module in a second angular direction.

FIG. 7 is an end view of a portion of the conveyor system of FIG. 1,illustrating a braking function provided by angularly adjustable driverollers of the system.

FIG. 8A is an end of a portion of the conveyor system of FIG. 1,illustrating engagement of angularly adjustable drive rollers andconveyor belt drive rollers.

FIG. 8B is an end of a portion of the conveyor system of FIG. 1,illustrating disengagement of angularly adjustable drive rollers andconveyor belt drive rollers.

FIG. 9 is a top perspective view of a second embodiment of a portion ofa conveyor system.

FIGS. 10A-10C are top views of the conveyor system of FIG. 9,illustrating angular adjustment of drive rollers of the system to adjustdiverting angle.

FIGS. 11A and 11B are perspective views of an embodiment of a mechanismthat can be used to adjust the angulation of the drive rollers of theconveyor system of FIG. 9.

FIG. 12 is a detail view of an embodiment of joints that support ends ofdrive rollers in the conveyor system of FIG. 9.

DETAILED DESCRIPTION

As described above, existing conveyor systems that include conveyor beltrollers, although providing advantages over previous systems, still havelimitations. As described in the following, however, such limitationscan be overcome with a conveyor system that employs a drive mechanismcomprising free-spinning angularly adjustable rollers that controlrotation of rollers contained within a conveyor belt. In someembodiments, a conveyor belt comprises a plurality of longitudinallyoriented free-spinning rollers that are “driven” through contact withfree-spinning angularly adjustable rollers that are positioned below theconveyor belt. In such systems, objects can be diverted at variousangles to either side of the conveyor belt through mere actuation of theangularly adjustable rollers. Furthermore, when the angularly adjustablerollers are aligned with the direction of belt travel, the conveyor beltrollers can be braked such that they will not rotate, thereby reducingor eliminating object drift. Moreover, given that the angularlyadjustable rollers can be gradually rotated from the braking orientationto a desired diverting angle, the conveyor belt rollers can be graduallyaccelerated, thereby reducing or eliminating slip.

Referring to the figures, in which like numerals indicate correspondingparts throughout the several views, FIG. 1 illustrates an embodiment ofa portion of a conveyor system 100 that can be adjusted to divertobjects at various angles to either side of the system. As indicated inFIG. 1, the conveyor system 100 comprises a conveyor belt 102 and afield 104 of angularly adjustable “drive” roller modules 106. In theembodiment of FIG. 1, the conveyor belt 102 comprises a conveyor beltframe 108 that is composed of a plurality of transverse modular conveyorbelt sections 110. Within each conveyor belt section 110 is a pluralityof elongated conveyor belt links 112 that extend in the direction ofbelt travel 114 and connect to adjacent conveyor belt links of adjacentconveyor belt sections. By way of example, each conveyor belt link 112comprises a metal or plastic member having an opening 116 provided ateach of its opposed ends that receives a rod or shaft (not shown) thatpasses through the openings of conveyor belt links of adjacent conveyorbelt sections 110 so as to connect the conveyor belt sections to eachother.

Interposed between the conveyor belt links 112 are elongatedlongitudinally oriented free-spinning conveyor belt rollers 118. For thepurposes of this disclosure, the term “free-spinning” means that therollers are free to spin about their axes of rotation in either angulardirection. Therefore, the rollers 118 may be said to comprise “idler”rollers that will freely rotate in either angular direction when drivenby an appropriate force. In the embodiment of FIG. 1, the rollers 118are positioned such that their axes of rotation are parallel to thedirection of belt travel 114. As shown in FIG. 1, the rollers 118 can bealternately provided along the width of each conveyor belt section 110in relation to the conveyor belt links 112 such that a roller ispositioned between each pair of adjacent conveyor belt links. In such anarrangement, the rollers 118 of the various conveyor belt sections 110can be arranged in columns 120 that extend in the direction of belttravel 114 and rows 121 that extend across the width of the conveyorbelt 102. It is noted that, although the rollers 118 have been describedand depicted as being elongated, the rollers need not necessarily beelongated in the direction of their axes of rotation.

The conveyor belt rollers 118 are made of metal and/or plastic and areprovided with a rubber or plastic high-friction outer layer or coatingthat prevents slippage when rollers of the roller modules 106 arebrought into contact with the conveyor belt rollers. Each roller 118 canconnect at each of its ends to the conveyor belt frame 108 and/or to therods or shafts that connect the various conveyor belt sections 110. Asindicated in FIG. 7, the rollers 118 are dimensioned so as to extendbeyond the upper and lower surfaces of the conveyor belt frame 108 (andbelt links 112) such that they can both divert objects placed on theconveyor belt 102 and can be driven from below by the drive rollermodules 106.

With further reference to FIG. 1, the field 104 of angularly adjustabledrive roller modules 106 comprises a plurality rows 122 and columns 124of drive roller modules. The drive roller modules 106 are positionedsuch that their columns 124 align with the columns 120 of the conveyorbelt rollers 118 and their rows 122, at least intermittently duringconveyor system operation, align with rows 121 of conveyor belt rollers.In the first embodiment shown in FIG. 1, the drive roller modules 106comprise relatively short (in the dimension of their axes of rotation)caster rollers (see FIGS. 2A and 2B) that are positioned closely enoughto each other such that at least one drive roller is aligned with anygiven conveyor belt roller 118 during the operation. Indeed, in theembodiment of FIG. 1, the drive roller modules 106 are positionedclosely enough such that at least two drive rollers are positionedadjacent any given conveyor belt roller 118, during conveyor operation.

Turning to FIGS. 2A and 2B, which illustrate perspective views of asingle drive roller module 106, each drive roller module includes afree-spinning drive roller 125 that is free to rotate in either angulardirection relative to its axis of rotation. Accordingly, althoughdesignated as “drive” rollers, the drive rollers 125 are not themselvesdriven by some mechanical means, such as a motor or the like. By way ofexample, each drive roller 125 is made of metal and/or plastic and, likethe conveyor belt rollers 118, has a rubber or plastic high-frictionouter layer or coating.

As shown in FIGS. 2A and 2B, the drive roller 125 is supported within aframe 126 that comprises opposed vertical support members 128. Extendingbetween the support members 128 and through a central opening providedin the drive roller 125 (not shown) is a shaft 130 about which the driveroller can rotate (i.e., the axis of rotation). In addition to thesupport members 128, the frame 126 comprises first and second controlarms 131 and 132 that, as described below, can be used to pivot thedrive roller module 106 about a central vertical axis 134 to adjust theangle of the roller 125 relative to the direction of belt travel 114(FIG. 1). As indicated in FIGS. 2A and 2B, each control arm 131, 132comprises an opening 133 that enables pivotal connection to anappropriate member that is used to adjust the angular orientation of thedrive roller module 106.

As best shown in FIG. 2B, the frame 126 further includes a base 135 anda pivot mechanism 137 that supports the base. In the embodiment of FIG.2B, the pivot mechanism 137 comprises upper and lower portions 139 and141 that can rotate in opposite directions relative to each other andthereby enable pivoting of the drive roller module 106. Suitablefriction reducing elements, such as bearings, can be provided betweenthe portions 139 and 141 to facilitate such pivoting.

FIG. 3 illustrates a further portion of the conveyor system 100. Moreparticularly, FIG. 3 illustrates interaction between the drive rollers125 and the conveyor belt rollers 118. Notably, the conveyor belt frame108 is not shown in the figure for purposes of clarity in describingother components of the conveyor system 100.

As indicated in FIG. 3, the drive rollers 125 are positioned so as tocontact the conveyor belt rollers 118 such that movement of the conveyorbelt 120 in the direction of belt travel 114 causes rotation of both thedrive rollers and the conveyor belt rollers due to the frictional forcesbetween them. In the orientation shown in FIG. 3, the drive rollers 125rotate in a downstream direction indicated by arrow 136. As aconsequence of that rotation, the conveyor belt rollers 118 are causedto rotate, or are “driven,” about their shafts 138 (i.e., axes ofrotation) in the direction indicated by arrow 140. Accordingly, in FIG.3, the conveyor belt rollers 118 rotate counterclockwise (when viewingthe conveyor belt 102 from its end looking upstream) and would thereforedivert objects supported by the conveyor belt rollers to the left in theorientation of the figure. As is further shown in FIG. 3, each conveyorbelt roller 118 is driven in the above manner by multiple drive rollers125.

As described above, the drive roller modules 106, and therefore thedrive rollers 125, can be pivoted about their central vertical axes 134(FIGS. 2A and 2B) to adjust their angulation relative to the directionof belt travel. The drive rollers 125 can be independently actuated oractuated in synchrony in groups. FIG. 4 illustrates a mechanism forenabling the latter actuation scheme (conveyor belt 102 not shown). Asindicated in FIG. 4, a plurality of rows 142 and columns 144 of driveroller modules 106 are provided having the general configurationdescribed in relation to FIG. 2. As is further indicated in FIG. 4, therows 142 of drive roller modules 106 are linked together with linkingmembers 146 that control the angular orientation of the rollers 125.More particularly, control arms 132 of the drive roller modules 106 arepivotally connected to a linking member 146, which can take the form ofa rod or shaft. By way of example, that connection is made with pins(not shown) that extend through the openings 133 (FIGS. 2A and 2B)provided in the control arms 132 of the drive roller modules 106 andinto aligned openings (not shown) of the linking member 146. When theposition of each drive roller module 106 is fixed relative to itscentral vertical axis 134, for example due to fixation of the lowerportion 141 of the pivot mechanism 137 (FIGS. 2A and 2B), transversedisplacement of the linking members 146 in the directions indicated byarrow 148 causes the rollers 125 to pivot about the central verticalaxes, thereby adjusting their angular orientation.

The linking members 146 can be displaced by any appropriate means. Inembodiments in which multiple linking members 146 are to besimultaneously displaced, and therefore multiple rows of rollers 125 areto be simultaneously pivoted, the linking members can be connected to asingle actuation member 150 that is positioned adjacent either side ofthe conveyor system 100 and pivotally connected to control arms 131 ofan adjacent column 144 of drive roller modules 106. In such a case,longitudinal displacement of the actuation member 150 in the directionsindicated by arrow 151 will cause pivoting of the adjacent column 144 ofdrive roller modules 106, which therefore causes the linking members 146to laterally translate, which, in turn, causes the remaining driveroller modules to pivot.

FIGS. 5A and 5B illustrate the effect of angular adjustment of the driveroller modules 106. Notably, the conveyor belt frame 108 is not shown inFIGS. 5A and 5B for purposes of clarity in describing other componentsof the conveyor system 100. Beginning with FIG. 5A, the drive rollermodules 106 have been pivoted in a counterclockwise direction (when theconveyor belt 102 is viewed from above) to cause counterclockwiserotation (when the conveyor belt is viewed from its end lookingupstream) of the conveyor belt rollers 118, as indicated by arrow 152.Such rotation of the conveyor belt rollers 118 causes diverting actionin a leftward direction in the orientation of FIG. 5A, so as to displacean object, O, in the direction of arrow 154. In FIG. 5B, however, thedrive roller modules 106 have been pivoted in a clockwise direction(when the conveyor belt 102 is viewed from above) to cause the conveyorbelt rollers 118 to rotate in a clockwise direction (when the conveyorbelt 102 is viewed from its end looking upstream) indicated by arrow 155to cause diverting action in a rightward direction and displace theobject, O, in the direction of arrow 156.

FIGS. 6A and 6B illustrate the variability of diverting angles possiblewith the drive roller modules 106. As indicated in FIG. 6A, each driveroller module 106 can potentially be taken from a 0 degree orientation,in which the axis of rotation of the roller 125 is perpendicular to thedirection of conveyor belt travel, to some negative angle represented byα. As indicted in FIG. 6B, the drive roller module 106 can also be takenfrom the 0 degree orientation to some positive angle represented by β.In some embodiments, both α and β can comprise any angle from 0 to 90degrees, thereby equating to 180 degrees of angular variability.Although such a broad range of angular variability is possible, conveyorbelt speed and limitations of the materials used for the drive rollers125 and conveyor belt rollers 118 may limit the range of angularorientations in which roller slip can be avoided. However, angularranges of at least approximately −70 degrees to 70 degrees areachievable at conveyor belt speeds of at least 100 feet/minute usingknown high-friction surfaces. Notably, the angular displacement of thedrive rollers 125 directly corresponds to the resultant diverting angle.For example, when the drive rollers 125 are oriented 35 degreesclockwise of the 0 degree orientation as shown in FIG. 6A, a 35 degreediverting angle to the right direction results.

When the drive rollers 125 are positioned in the 0 degree orientationshown in FIG. 7, in which the axes of rotation of the drive rollers areperpendicular to the direction belt travel and the direction of angularrotation of the drive rollers is in line with the direction of belttravel, the conveyor belt rollers 118 are substantially prevented fromrotating and are therefore “braked.” Accordingly, undesired lateralmovement of objects on the conveyor belt can be prevented, if desired,by controlling the drive roller modules 106, to be placed in the 0degree orientation. It is further noted that when the angularorientation of the drive rollers 125 is adjusted from the 0 degreeorientation as an initial position, the conveyor belt rollers 118 can begradually accelerated in one direction or the other, thereby decreasingor all together preventing the roller slip that can occur when afriction plate or angled rollers suddenly engage the conveyor beltrollers. Gradual acceleration of the conveyor belt rollers 125 alsoenables relatively unstable objects to be diverted without tipping over.For instance, if an object to be diverted is relatively tall and has arelatively small base, the object can be gradually accelerated to oneside or the other of the conveyor belt 102 by slowly increasing theangulation of the drive rollers from the 0 degree orientation.

In addition to being angularly adjustable, the drive roller modules 106can, optionally, be vertically actuated to engage or disengage the driverollers 125 with conveyor belt rollers 118. Such functionality isdepicted in FIGS. 8A and 8B. In particular, FIG. 8A illustrates thedrive rollers 125 in engagement with the conveyor belt rollers 118,while FIG. 8B illustrates the drive rollers disengaged from the conveyorbelt rollers. Such selective engagement and disengagement can beprovided with an appropriate mechanism (not shown) that lifts the driverollers 125 into contact with the conveyor belt rollers 118 and lowersthe drive rollers out of contact with the conveyor belt rollers.

From the above it can be appreciated that several advantages can beachieved through use of conveyor systems that comprise angularlyadjustable rollers that drive rollers contained within a conveyor belt.For example, objects can be diverted to either side of the conveyorsystem at various angles. In addition, the conveyor belt rollers can bebraked to control object drift across the conveyor belt. Furthermore,the conveyor belt rollers can be accelerated to some desired angularvelocity with virtually no slip.

It is noted that other advantages can also be realized with suchconveyor systems. For example, discrete groups of drive rollers can beoperated in different zones of the conveyor system not only along thedirection of travel of the conveyor belt but also along the width of theconveyor belt through the provision of discrete control mechanisms(e.g., linking members). In such cases, the positions of objects on theconveyor belt can be controlled with great precision by individuallycontrolling the drive rollers of the different zones. In fact, when a“smart” detection and control system is provided, such as animaging-based system, individual objects can be identified and preciselymoved along and/or across the belt, for example to enable desiredordering and/or alignment of the objects on further conveyor belts onwhich the objects are to be placed.

Turning to FIG. 9, illustrated is a second embodiment of a portion of aconveyor system 200. As indicated in that figure, the conveyor system200 is similar in several ways to the conveyor system 100 shown inFIG. 1. Therefore, the conveyor system 200 generally comprises aconveyor belt 202 that includes a plurality of longitudinally orientedfree-spinning conveyor belt rollers 204. The conveyor belt 202 travelsin a direction of belt travel identified by arrow 206. In addition, thesystem 200 comprises a plurality of free-spinning angularly adjustabledrive rollers 208. In the system 200, however, the drive rollers 208 areelongated, or “longitudinal,” rollers instead of caster rollers. In theembodiment shown in FIG. 9, the drive rollers 206 are longer than theconveyor belt 202 is wide.

FIGS. 10A-10C illustrate angular adjustment of the drive rollers 208relative to the conveyor belt 202. In particular, assuming a conveyorbelt direction of travel indicated by arrow 206, FIG. 10A illustrates anangulation of the drive rollers 208 that results in the diverting ofobjects to the left, FIG. 10B illustrates the “braking” orientation ofthe drive rollers, and FIG. 10C illustrates an angulation of the driverrollers that results in the diverting of objects to the right.

As with the conveyor system 100, the drive rollers 208 can be angularlyadjusted using a variety of adjustment mechanisms. FIGS. 11A and 11Billustrate one such mechanism (conveyor belt not shown for purposes ofclarity). As shown in those figures, the drive rollers 208 can bepivotally supported by a rectangular frame 210 comprising multiple framemembers 212 that are pivotally connected to each other at pivot joints214 located at corners of the frame. By way of example, each pivot joint214 is formed by leaves of the frame members 212 that interleave witheach other and are secured together with a pin or shaft (not shown).With such a configuration, orientation of the frame 210 can be changedfrom the orthogonal orientation shown in FIG. 11A, in which the framemembers 212 form approximately 90 degree angles at each of the cornersof the frame, to another orientation at which two acute angles and twoobtuse angles are formed at the frame corners, as shown in FIG. 11B,thereby placing the frame into a parallelogram shape. In the orthogonalorientation of FIG. 11A, the drive rollers 208 are aligned so as to beperpendicular to the direction of belt, as indicated in FIG. 10B.Therefore, the orthogonal orientation of FIG. 11A is the brakingorientation. At other orientations, however, such as that indicated inFIG. 11B, the drive rollers 208 are oriented such that they arepositioned at an angle relative to the direction of belt travel, therebyproviding the diverting function.

Each drive roller 208 is supported at both ends by a joint that permitsthe change in orientation as well as free rotation. With reference tothe detail view of FIG. 12, each drive roller 208 can, for example, besupported by a shaft 215 having “eye” connectors 216 configured toreceive a pin 218 that extends through a support bracket 220 that ismounted to a frame member 212.

Returning to FIGS. 11A and 11B, the frame 210 can be manipulated in themanner described above by, for example, using an actuator 222. In theembodiment shown in FIGS. 11A and 11B, the actuator 222 comprises apiston member having a piston body 224 from which a piston arm 226 canbe extended, for instance under the influence of hydraulic or pneumaticpressure. Both the piston body 224 and the piston arm 226 are pivotallyconnected to adjacent frame members 212 with mounting brackets 228. Withsuch an arrangement, retraction of the piston arm 226 into the pistonbody 224 results in angular adjustment of the drive rollers 208 in afirst angular direction, while extension of the piston arm from thepiston body results in angular adjustment of the drive rollers in asecond, opposite angular direction. Such manipulation is evident fromFIGS. 11A and 11B. In particular, FIG. 11A illustrates a first extent ofextension of the piston arm 226 from the piston body 224 and a firstorientation of the drive rollers 208, while FIG. 11B illustrates asecond (greater) extent of extension of the piston arm from the pistonbody and a second orientation of the drive rollers. Through appropriateextension and retraction of the piston arm 226, the orientation of thedrive rollers 208 can be precisely controlled and diverting of objectscan be achieved to either side of the conveyor belt 202 at variousdiverting angles as depicted in FIGS. 10A-10C.

While particular embodiments have been disclosed in detail in theforegoing description and drawings for purposes of example, it will beunderstood by those skilled in the art that variations and modificationsthereof can be made without departing from the scope of the disclosure.In one such variation, the axles of the conveyor belt rollers can serveas the tensioning members of the conveyor belt. In such a case, theconveyor belt frame and its links can be omitted to enable higher rollerdensity. In addition, such an arrangement may reduce the possibility ofitems being pulled down into the conveyor belt when the belt rollers arespinning because the surfaces of adjacent rollers move in oppositedirections and the downward force of one spinning roller may benullified by the upward force of the adjacent spinning roller.

1. A conveyor system comprising: a conveyor belt having a plurality ofconveyor belt rollers configured to divert objects on the conveyor belt;and a drive mechanism that engages the conveyor belt rollers, the drivemechanism being configured to drive the conveyor belt rollers, the drivemechanism being adjustable such that at least one individual conveyorbelt roller can be selectively rotated in a first angular direction anda second angular direction so that objects can be selectively divertedto either side of the conveyor belt at a desired diverting angle.
 2. Thesystem of claim 1, wherein the conveyor belt rollers have axes ofrotation that are aligned with a direction of travel of the conveyorbelt such that the conveyor belt rollers can divert objects in eithertransverse direction across the conveyor belt.
 3. The system of claim 1,wherein the conveyor belt rollers are elongated in a direction of theiraxes of rotation.
 4. The system of claim 1, wherein the drive mechanismcomprises a plurality of free-spinning angularly adjustable driverollers that engage the conveyor belt rollers, such engagement causingthe conveyor belt rollers to rotate when a direction of rotation of thedrive rollers is not aligned with a direction of belt travel.
 5. Thesystem of claim 4, wherein the angularly adjustable drive rollers can beadjusted from an orientation in which they rotate in a direction in linewith the direction of belt travel to orientations in which they rotatein directions that form an angle with the direction of belt travel. 6.The system of claim 5, wherein the greater the angle between thedirection of drive roller rotation and the direction of belt travel thegreater a diverting angle at which objects are diverted by the conveyorbelt.
 7. The system of claim 5, wherein the diverting angle can extendfrom approximately −90 degrees to approximately 90 degrees relative tothe direction of belt travel.
 8. The system of claim 5, wherein thediverting angle can extend from at least approximately −70 degrees to atleast approximately 70 degrees relative to the direction of belt travel.9. A conveyor system comprising: a conveyor belt having a plurality offree-spinning conveyor belt rollers configured to divert objects acrossthe conveyor belt, the conveyor belt rollers having axes of rotationthat are aligned with a direction of travel of the belt such that theconveyor belt rollers can divert objects in either transverse directionacross the conveyor belt; and a plurality of free-spinning angularlyadjustable drive rollers that engage the conveyor belt rollers, suchengagement causing the conveyor belt rollers to rotate when a directionof rotation of the drive rollers is not aligned with the direction ofbelt travel, wherein the angular orientation of the drive rollers can beadjusted relative to the direction of belt travel to change a divertingdirection and a diverting angle of the conveyor belt.
 10. The system ofclaim 9, wherein the conveyor belt rollers are elongated in a directionof their axes of rotation.
 11. The system of claim 9, wherein theangularly adjustable drive rollers can be adjusted from an orientationin which they rotate in a direction in line with the direction of belttravel to orientations in which they rotate in directions that form anangle with the direction of belt travel, the angle being equivalent inmagnitude to the diverting angle.
 12. The system of claim 11, whereinthe diverting angle can extend from approximately −90 degrees toapproximately 90 degrees relative to the direction of belt travel. 13.The system of claim 11, wherein the diverting angle can extend from atleast approximately −70 degrees to at least approximately 70 degreesrelative to the direction of belt travel.
 14. The system of claim 9,wherein the angularly adjustable drive rollers can be selectivelyengaged with and disengaged from the conveyor belt rollers.
 15. Thesystem of claim 9, wherein the angularly adjustable drive rollerscomprise relatively short caster rollers.
 16. The system of claim 15,wherein at least two angularly adjustable drive rollers are positionedadjacent a conveyor belt roller during conveyor operation.
 17. Thesystem of claim 15, wherein the angularly adjustable drive rollers arealigned in rows transverse to the direction of belt travel and columnsaligned with the direction of belt travel.
 18. The system of claim 15,wherein at least some of the angularly adjustable drive rollers areindependently actuable such that an angular orientation of at least someof the drive rollers can be independently controlled.
 19. The system ofclaim 15, wherein at least some of the angularly adjustable driverollers are actuable together in groups such that an angular orientationof at least some of the drive rollers can be controlled in synchrony.20. The system of claim 9, wherein the angularly adjustable driverollers are elongated in a direction of their axes of rotation.
 21. Thesystem of claim 20, wherein the angularly adjustable drive rollers aresupported by a frame, an orientation of the frame being adjustable, andwherein when the orientation of the frame is adjusted, orientations ofthe drive rollers are adjusted in synchrony.
 22. A conveyor systemcomprising: a conveyor belt having a frame and a plurality offree-spinning conveyor belt rollers supported by the frame, the conveyorbelt rollers extending above and below top and bottom surfaces of theframe and being configured to divert objects across the conveyor belt,the conveyor belt rollers having axes of rotation that are aligned witha direction of travel of the belt such that the conveyor belt rollerscan divert objects in either transverse direction across the conveyorbelt, the conveyor belt rollers being elongated along their axes ofrotation; and a plurality of free-spinning angularly adjustable driverollers that can be selectively engaged with and disengaged from theconveyor belt rollers from a position below the conveyor belt, angularorientations of the drive rollers being adjustable relative to thedirection of belt travel such that the drive rollers can be selectivelypositioned from an orientation in which, through engagement with theconveyor belt rollers, the drive rollers rotate in the direction of belttravel to orientations in which the drive rollers rotate in directionsother than the direction of belt travel; wherein drive roller rotationin the direction of belt travel brakes the conveyor belt rollers so thatthey will not rotate and drive roller rotation in directions other thanthe direction of belt travel drives the conveyor belt rollers due tofrictional forces between the drive rollers and the conveyor beltrollers; wherein angular orientations of the drive rollers can beadjusted such that the drive rollers rotate in directions that formsubstantially any angle from at least approximately −70 degrees to atleast approximately 70 degrees relative to the direction of belt travel.23. The system of claim 22, wherein the angularly adjustable driverollers comprise relatively short caster rollers that are aligned inrows transverse to the direction of belt travel and columns aligned withthe direction of belt travel.
 24. The system of claim 23, wherein atleast two angularly adjustable drive rollers are positioned adjacent aconveyor belt roller during conveyor operation.
 25. The system of claim23, wherein at least some of the angularly adjustable drive rollers areindependently actuable such that an angular orientation of at least someof the drive rollers can be independently controlled.
 26. The system ofclaim 22, wherein the angularly adjustable drive rollers are elongatedin a direction of their axes of rotation and are at least as long as theconveyor belt is wide.
 27. The system of claim 26, wherein the angularlyadjustable drive rollers are supported by a frame, an orientation of theframe being adjustable with an actuator, and wherein when theorientation of the frame is adjusted, orientations of the drive rollersare adjusted in synchrony.
 28. A method for diverting objects, themethod comprising: supporting the objects on a conveyor belt thatincludes a plurality of free-spinning conveyor belt rollers; engagingthe conveyor belt rollers with free-spinning angularly adjustable driverollers; and adjusting an angular orientation of the drive rollersrelative to a direction of belt travel to adjust a diverting angle ofthe conveyor belt.
 29. The method of claim 28, further comprisingadjusting the angular orientation of the drive rollers such that adirection of rotation of the drive rollers is in line with the directionof conveyor belt travel to brake the conveyor belt rollers.
 30. Themethod of claim 29, further comprising adjusting the angular orientationof the drive rollers from the orientation in which the direction ofdrive roller rotation is in line with the direction of conveyor belttravel to an orientation in which the direction of drive roller rotationforms an angle with the direction of belt travel so as to cause theconveyor belt rollers to accelerate from zero angular velocity to afinal angular velocity.